+ virtual int DoInsert(const wxString& item, unsigned int pos) = 0;
+
+ virtual void DoSetItemClientData(unsigned int n, void* clientData) = 0;
+ virtual void* DoGetItemClientData(unsigned int n) const = 0;
+ virtual void DoSetItemClientObject(unsigned int n, wxClientData* clientData) = 0;
+ virtual wxClientData* DoGetItemClientObject(unsigned int n) const = 0;